In a congressional race that is drawing national attention, a seemingly existential question has turned up the heat: Just when does a political campaign begin?

In the case of Republican front-runner Brian Fitzpatrick, his opponents say his first steps into the contest may have been missteps.

Less than two months after suddenly entering the race and instantly becoming the favorite, Fitzpatrick is facing criticism and questions about a report that he began his campaign before resigning from his FBI post.

At issue is the Hatch Act, which prohibits government employees from participating in political activities, including running for public office.

Last week, Politico reported that Fitzpatrick, while still working as an agent, allowed his brother, Rep. Mike Fitzpatrick (R., Bucks), to make campaign calls on his behalf.

The federal office that regulates the Hatch Act defines a campaign as any "preliminary activities, completed either by the candidate or someone on his or her behalf."

The allegations have sparked speculation from both parties' candidates about whether Brian Fitzpatrick began any campaign work while at the FBI. He left his job in the bureau's public corruption unit one week before launching the bid to replace his brother in Congress.

A Bucks County resident said she planned to submit a formal complaint against Brian Fitzpatrick by the end of next week.

However, while Hatch Act violations can lead to federal employees' leaving their jobs or dropping out of races, only current employees can be investigated for violations.

When the Office of Special Counsel, which handles violations, gets a complaint involving a former employee, it responds with a letter stating it no longer has jurisdiction and will take no further action, the office said.

Still, opponents are thrashing Fitzpatrick over the accusations and raising broader questions about his quick candidacy.

His spokeswoman has responded by calling the allegations "dirty tricks from a political machine threatened by Brian Fitzpatrick."

His late entry shook up the contest for the Eighth District seat, which covers all of Bucks County and a small portion of Montgomery County.

With no incumbent - Mike Fitzpatrick is retiring - the seat is up for grabs in one of the few districts in the country nearly evenly divided between Democrats and Republicans.

After resigning his FBI post, Brian Fitzpatrick announced his run on Jan. 21, 10 days after a deed for a Bucks County residence was recorded in his name, property records show.

Less than two weeks later, State Rep. Scott Petri, then considered the Republican front-runner, dropped out. By Feb. 11, Fitzpatrick had the endorsement of the county GOP committee. He is also backed by the National Republican Congressional Committee.

The county GOP chair, Pat Poprik, said she had not been contacted by the Brian Fitzpatrick campaign until late January. She is married to John Poprik, who is listed in FEC filings as the treasurer of Brian Fitzpatrick for Congress and who was Mike Fitzpatrick's campaign treasurer.

Marc Duome, another GOP candidate, said he felt the county party had been pushed to recommend a certain candidate.

"There was a sense that a lot of the endorsement process was pretty much a done deal very early," he said.

Andy Warren, the third Republican running, said the questions surrounding the campaign were "a shame" and showed a lack of judgment by the Fitzpatrick brothers.

"What did they expect, really, if somebody comes flying in from 3,000 miles away?" he said. "I don't know that that should be a surprise to anyone that ... people might look askance."

Democrats have called on Fitzpatrick to answer questions about how he completed all the activities necessary to start a campaign within the week after his resignation.

"Is he asking us to believe he quit his job at the FBI, moved 3,000 miles across the country [from California], launched a campaign for Congress and [got] the county party's endorsement without ever picking up the phone?" Democratic candidate Shaughnessy Naughton said Thursday.

In a statement, State Rep. Steve Santarsiero, the other Democrat running, said, "If true, [a violation] would raise serious questions for which the public should demand answers. No one should be above the law."

Brian Fitzpatrick's spokeswoman called the allegations unfounded in her statement but has not otherwise addressed when campaign work began. On Thursday, the spokeswoman was said to be on vacation.

A spokesman for Mike Fitzpatrick said there was no one in his office who could answer questions about the race.

Brian Fitzpatrick said in January that he decided to run while on assignment in Ukraine over the summer, and said he did not begin campaign discussions until after his resignation.

As for his older brother's influence, Fitzpatrick said then, "Mike just gives advice."

610-313-8205@McDanielJustine

Staff writer Jonathan Tamari contributed to this article.